Reusable concrete form tie



AVPTI 8Q1969 t D. TAUsANovlTcH 3,437,309

REUSABLE CONCRETE FORM TIE Filed sept. 2e, 196s DUSQN TQusHNovlTcH ATTO @Nev United States Patent O 3,437,309 REUSABLE CONCRETE FORM TIE Dusan Tausanovitch, Greenwich, Conn. (1 Crestwood Drive, RJD. 1, Northport, N .Y. 11768) Filed Sept. 26, 1966, Ser. No. 581,908 Int. Cl. E04g 17/06 U.S. Cl. 249-216 4 Claims ABSTRACT F THE DISCLOSURE The present invention relates to the molding of concrete structures by means of a form, particularly to an improved tie for such forms, and has for its primary object to provide an improved tie that can be used over and over again.

Usually, concrete structures are formed in wooden or steel forms, which are connected and held in place against lateral pressure of unhardened concrete by form ties. One embodiment of form tie in common use is a continuous single round steel rod with ltwo washers, which act as spacers between two adjacent form faces. Two collars adjacent the endv of the steel rod and interiorly of the washers, provide support therefor and maintain the washers at a predetermined distance apart. The ends of the tie rod extend through the for-m for connection with various holding devices which engage and support the outer form members. Because of rust marks, concrete specifications often require that no metal be left closer than l to 2 to the surface of the concrete. To comply with this, the tie rod is provided at its end portions with two weakened sections, break points, at a specified distance from the concrete face to facilitate removal of the exposed tie ends.

Another embodiment of a conventional form tie includes one intermediate threaded part with a pair of end bolts in which the intermediate part remains in the concrete after the end bolts are removed.

The holes that are left in the concrete, after removal of the tie ends or bolts, are patched by concrete grout. A good, well bonded patch over the tie rod end is essential. If any moisture penetrates the concrete to the tie end, rust will form thereon and eventually appear on the concrete face.

Frusto-conical members, made of wood, steel or plastic material, commonly called cones, are often specied for both of the above tie embodiments in order to obtain better conditions and uniform holes for patching the same after removal of the tie ends.

Heretofore, many types of concrete forming ties have been proposed to facilitate complete removal thereof from the concrete Wall, but none of these ties has been completely satisfactory. Prior art arrangements are described in U.S. Patents Nos. 1,907,618, 2,029,147, 2,133,- 574, 2,234,784, 2,335,236, 2,486,683, 2,968,855 and 3,057,034.

Accordingly another object of the present invention is to provide such form ties, which can be removed from the concrete structure without destruction thereof or damage to the concrete structure.

Still another object is to provide such form ties, which are simple, practical and economical in construction.

3,437,309 Patented Apr. 8, 1969 ICC A further object is to provide such form ties, which can be used in various forming systems.

Other and further objects will be obvious upon an understanding of the illustrative embodiments about to be described, or will be indicated in the appended claims, and various advantages not referred to herein will occur to one skilled in the art upon employment of the invention in practice.

In the drawing:

FIG. 1 is a vertical sectional View of a concrete Wall and illustrates one embodiment of forming ties, namely, of a continuous single steel rod, in the conventional forming method and in accordance with the present inventon.

FIG. 2 is a vertical sectional view of the concrete wall with the form removed and illustrating the manner of extraction of the tie.

FIG. 3 is a longitudinal sectional view of a modified form tie, provided with two end cones.

FIG. 4 illustrates another embodiment of forming ties of the internal disconnecting type, with two end bolts in accordance with the present invention.

Referring now to FIG. 1 of the drawing in detail, there is shown a conventional form 10 for a concrete wall 11 and a form tie 12 for holding the form together. The form 10 comprises upright sheeting 14, vertical studs 15, horizontal wales 16 and a holding device, such as a steel wedge 13.

As shown in FIGS. 1 and 2, the `form tie 12 comprises an elongated yieldable tube 17 lodged in the wall and extending substantially from one side of the wall to the other, a washer 18 permanently secured across the tube 17 at each end thereof, and a rigid metallic tie rod 19 slidably mounted in and extending through and beyond the tube 17 and the washers 18. The portion of the tie rod 19 within the tube 17 has two formations 20 each facing washer 1S. These formations are shown as collars but could be circumferentially spaced projections. The tie rod 19 is usually made of round steel, but could be of any cross section or of any metal or plastic material and of any required strength. The distance between the washers 18 varies and depends upon the size of the concrete structure to be formed. The washers 18 are of slightly smaller diameter than the tube 17 and may have beveled edges to facilitate breaking of the concrete bond. The tube 17 may be formed of any material which is readily stretched, for example, rubber or a plastic having elastic square, rectangular, triangular or polygonal in cross-section. The ends of the tube 17 are firmly connected to the washers 18 by 1conventional means, such as by structural adhesives, mechanical means or both.

It will be of course understood that the embodiment characteristics of rubber. The tube, the bore of the tube and the middle of the tie rod may be circular, elliptical, shown in FIG. 1 illustrates the use of the form tie of this invention in a conventional concrete forming structure. As mentioned heretofore, exposed ends of the tie 19 may be modified as required in length and in shape or both for connection with any holding devices, as forming clamps or brackets used in various forming systems without departing from the spirit of invention.

After dismantling the form 10, as shown in FIG. 2, the form tie is extracted by pulling one end of the tie rod 19, for example at the left, as shown by the arrow, so that the formation 20 at the left engages the inner face of the washer 18 at the left. Continued pulling of the tie rod 19 causes the formation 20 to exert a force on the left washer 18, which by being permanently secured to the tube 17 pulls the tube. As the tube 17 is being pulled, while resisting extraction, the tube is elongated and its diameter is reduced, whereby the other peripheral surface of the tube is gradually released from the concrete wall surface defining the passage. Thus it is evident that the contraction of the tube 17 breaks the concrete bond along the tube length and facilitates removal of the form tie from the concrete. This is accomplished without destruction of the form tie and without disruption of the passage.

In FIG. 3, a form tie 12 is shown which is essentially like the tie already described, except that a frusto-conical member 21, termed a forming cone, is added and secured to each end of the tube 17 and overlies the washer 18. This arrangement facilitates tie extraction. The members 21 have a central bore 22 so dimensioned as to enable a head 24 at one end of the tie rod to enter the same.

The members 21 act as spreaders and permit use of smaller size washers 18 and tubes 17. This results in smaller passages left in the concrete to comply with special requirements. The members may be made of wood, metal or plastic.

In FIG. 4 is shown another embodiment of concrete forming tie, which comprises a tube 17, washers 18 and a tubular tie rod 25 having threaded internal bores at its end portions for threaded engagement with removable bolts 26. The end faces ofthe rod 25 constitute formations for engaging the inner faces of the Washers 18. Extraction of the tie rod is similar to that described hereinbefore. If desired, cones 21, such as shown in FIG. 3, may be secured to the ends of the tube 17 of the form tie shown in FIG. 4.

From the foregoing description, it will be seen that the present invention provides improved and economical form ties that can be reused repeatedly in the construction of concrete forms.

As various changes may be made in the form, construction, and arrangement of parts herein, without departing from the spirit and scope of the invention and without sacrificing any of its advantages, it is to be understood that all matters are to be interpreted as illustrative and not in any limiting sense.

What is claimed is:

1. A tie for concrete forms comprising an elongatable, yieldable tube for forming a passage extending through the concrete form, washer means permanently secured across said tube at least at one end of said tube, and a rigid tie rod slidably mounted in and extending through said tube and said washer means, said tie rod having two collars thereon each for engaging an inner face of one of said washer means, whereby when pulling said tie rod in a direction to cause one of said collars to exert a force on said one of said Washer means said tube is elongated to reduce its diameter, whereby a bond between said tube and concrete is broken and the tube is released from the wall defining the passage, so that the rod assembly can be withdrawn without destruction thereof.

2. A tie for concrete forms comprising an elongatable, yieldable tube for forming a passage extending through the concrete form, washer means permanently secured across said tube at least at one end of said tube, a rigid tie rod slidably mounted in and extending through said tube and said washer means, said tie rod having at least one formation thereon for engaging an inner face of at least one of said washer means, whereby when pulling said tie rod in a direction to cause said formation to exert a force on said one of said washer means said tube is elongated to reduce its diameter, whereby a bond between said tube and concrete is broken and the tube is released from the wall defining the passage, so that the rod assembly can be Withdrawn without destruction thereof, and a frusto-conical member secured to each end of said yieldable tube and overlying said Washer means, said frustoconical members cach having a bore through which said tie rod extends.

3. A form tie according to claim 2, wherein said tie rod has a head at each end thereof for engaging an outer surface of the form.

4. A form tie according to claim 3, wherein said bores are dimensioned to enable said head to enter the same.

References Cited UNITED STATES PATENTS 1,907,618 5/1933 Umbach et al 249-217 2,046,674 7/ 1936 Coates 249-42 2,164,625 7/1939 Prosser et al. 2,602,979 7/1952 Van Buren. 3,181,832 5/1965 Chianese 249-43 I. SPENCER OVERHOLSER, Primary Examiner.

J. S. BROWN, Assistant Examiner.

U.S. Cl. X.R. 249-43.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 ,437 ,309 Dated April 8 1969 Inventor) Dusan Tausanovitch It is certififedthat error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 2 line 46 after "elastic" insert characteristics of rubber The tube., the bore of the tube and the middle of the tie rod may be circular, elliptical Signed and sealed this 14th day of December 1971 (SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Acting Commissioner of Patents FORM IDO-1050 (1o-69) uscoMM-oc eos-:mp0s 

